Bell X-1A supersonic research aircraft with 1953 flight data. The flight data graph is from the record-breaking flight by Major Charles E. Yeager on 12 December 1953. After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed, California, USA. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or eight times the normal pull of gravity at sea level.